Quantum myth 3: nature is fundamentally random

[pellman]

We are discussing the Demystifier's paper "Quantum mechanics: myths and facts". http://xxx.lanl.gov/abs/quant-ph/0609163

Previously:
Myth 1 https://www.physicsforums.com/showthread.php?t=229497
Myth 2 https://www.physicsforums.com/showthread.php?t=230693

QM implies that nature is fundamentally random

The topic is the claim that the common statement that nature is fundamentally random--as opposed to merely unpredictable--is a myth. By myths we mean widely repeated statements which, true or false, are not something we can validly assert given our current understanding.

I don't have any questions about this section of the paper myself and have included it only for completeness sake. I'm ready to discuss any aspect anyone else wants to discuss.

However, I will add that I have a severe case of gut reaction against objective randomness. Consider an event which has possible outcomes A and B. The event occurs and we observe B instead of A. The claim that "the outcome of this event is random" can only mean that if we ask, "Why did B occur and not A?" the answer must be "no reason; none." To say "B happened because .." is to identify that which determined B and that is to say it was not random. But this is to say, once again, that there is no reason that B occurred. Things just happen for no reason?? And somehow this multitude of things happening for no reason conspires to create the visible macro order? I can't accept that.

And to say "there is no reason B occurred," whether true or not, bugs me because it is a willful decision to stop looking. It is too much like the creationist who says that evolution can't explain all the facts so we should just accept that God did it. To attribute something to miracle or to it-just-happens, either one, is to just give up. Benjamin Franklin could just as well have shrugged his shoulders and said, "Who knows about lightning? It just happens."

(I don't have anything against miracles per se. I'm a theist. But scientists qua scientist should not incorporate them into the scientific approach since it necessarily puts an end to the method.)

We say of a supposed random event, "It could turn out A or B". Afterwards, we say that although B happened, it could have been A. What do we mean by "could have been"? B happened, period. I haven't thought it about long enough, and haven't read enough, but I suspect that the notion of "could have been otherwise" would turn out to have serious logical problems on close examination.

Just a hunch.

 

[peter0302]

I think a better definition of random is that under identical starting conditions, any two tries are not guaranteed to have the same result. This definition naturally excludes pseudorandomness or chaotic systems, as it is a fact that in such systems, though minute changes in starting conditions have drastic effects over time, identical starting conditions still yield identical results.

The problem, of course, is that thorugh this definition nothing can be proven to be ranodm because starting conditions can never be identical. To paraphrase Bell, the moons of Jupiter will be in different positions. So it is always possible that everything we observe now is inevitable based solely on the starting conditions at the time of the Big Bang, and that could the Big Bang be replicated in perfect detail, everything would transpire as it has here.

A philosophical argument in support of fundamental randomness is related to free will, obviously. Because if QM were not fundamentally random, that means that while thought processes may be chaotic and thus appear random, they are still fundamentally deterministic, and there is, thus, no such thing as "true" free will. We make our decisions based solely on where the electrons in our brains were preordained to go 12 billion years ago. This is not a comforting thought.

 

[pellman]

I always found the implications to free will that follow from the idea that my thoughts are random as being more disturbing than if they are deterministic. ;-)

 

[Hans de Vries]

I always found the implications to free will that follow from the idea that my thoughts are random as being more disturbing than if they are deterministic. ;-)

Indeed :rofl:

that means that while thought processes may be chaotic and thus appear random, they are still fundamentally deterministic, and there is, thus, no such thing as "true" free will. We make our decisions based solely on where the electrons in our brains were preordained to go 12 billion years ago. This is not a comforting thought.

The laws of nature would have to be precise for at least "12 billion" digits behind the
decimal point. Just to give some arbitrary high number. The way around the free will
dilemma is the fact that nature can never by infinitely accurate.

If physical processes in the femtosecond domain are totally deterministic to within
a precision of 10^-17 then your thoughts are predictable for about one minute or
so after which they start to deviate from the best possible prediction, assuming a
constant precision loss rate.

So, the free will dilemma isn't really a point in the determinism debate.


Regards, Hans.

 

[Ken G]

My take is that the mistake is thinking there are only two possibilities: deterministic but unpredictable, or fundamentally random. Both of those are models, I doubt reality is either.

 

[pellman]

I think that it is a possibility too, Ken. It also consistent with the inner experience which we call "free will", which we cannot quite put into words yet seems in contradiction to both strong determinism and randomness.

But if there is a possibility other than determinism or randomness, I can't grasp what it might be like. It could be that such a thing is incomprehensible to human brains. We should keep trying of course but I am not optimistic.

 

[Ken G]

It also consistent with the inner experience which we call "free will", which we cannot quite put into words yet seems in contradiction to both strong determinism and randomness.

Yes, that's one motivation for thinking "outside the box" of the determinism/random dichotomy. The other reason is simply that we should not impose our limited intelligence or reality, but rather seek descriptions of the latter using the former.

But if there is a possibility other than determinism or randomness, I can't grasp what it might be like. It could be that such a thing is incomprehensible to human brains.

It isn't incomprehensible to our brains, because we've conjured the concepts of "free will" and "God" and if you put those together you have another possibility to deterministic or random. It's not scientifically useful, but it's an example of an alternative. What we want is something that works with science, and that might be the rub. But we never really know what is comprehensible to our minds until a genius finds an angle that makes it understandable.

We should keep trying of course but I am not optimistic.

Hope springs eternal!

 

[reilly]

Something to note: in the Brain science, neurophysiology world, free will is an increasingly troubled concept. Not because of any problems with determinism or randomness, but rather because of the role of the unconscious. For example; I hate cooked turnips, but rather enjoy raw turnips --not a free choice. some folks completely lose it when cut off on the freeway -- for some, the limbic system takes over, which could lead to flipping the bird, to out-of-control road rage. Some, on the other hand, with mature impulse control, might simply mutter, "That's life..."; which could be consistent with free will, whereas road rage is not governed by free will. (I can dig up some references upon request, some of which deal with experiments.)

So free will is a serious candidate for mythological status, simply because it is no longer the exclusive property of philosophy, and is being subjected to the standard methods of scientific inquiry. "Take a look and see what happens."

Randomness? What immediately comes to mind is the classic book, A Random Walk Down Wall-Street, which by means of various statistical tests suggested that the
Dow Jones index is a random variable. When doing surveys or quality control or sales forecasting, or looking for rare events, randomness as always an issue. Is a random sample really random? Are there biases in quality control testing? The approach in practical circumstances is to rely on commonly accepted statistical tests -- in a sense,
this defines randomness in operational terms.

Remember, David Hume destroyed the idea of causality quite a long time ago, so, strictly speaking, the idea of determinism has been dead for several hundred years; apparently few went to the funeral. (His basic notion was;how in the world could you prove A caused B? He concluded, quite reasonably, that such a proof simply does not exist. So, to the extent that randomness means no cause -- like a regression R-squared of 0, with all possible independent variables --, randomness cannot be proved either.

So, yes randomness is indeed a myth, but ever so valuable a myth. Ditto for determinism, objective reality, and ...
Regards,
Reilly Atkinson

 

[pellman]

Something to note: in the Brain science, neurophysiology world, free will is an increasingly troubled concept. Not because of any problems with determinism or randomness, but rather because of the role of the unconscious. For example; I hate cooked turnips, but rather enjoy raw turnips --not a free choice. some folks completely lose it when cut off on the freeway -- for some, the limbic system takes over, which could lead to flipping the bird, to out-of-control road rage.

I don't grant this much significance yet, reilly. I can't say whether these observations made in brain science are incompatible with free will or not because I don't know what free will is. I can only think of the vaguest of definitions.

I can grant that dislike of cooked turnips may not be a free choice. No taste is, whether it is a taste for Beethoven or a taste for torturing young boys. But what about the choice to act or refrain from acting on that taste? Christians, Muslims, etc. would say therein is the free choice.

But what is a free choice? I can't isolate it to say for certain whether anything is a "free choice" or not.

I find it interesting that such a fundamental questions of physics could be at all related to a fundamental question of morality and/or religion.

 

[Ken G]

So, yes randomness is indeed a myth, but ever so valuable a myth. Ditto for determinism, objective reality, and ...

Bingo. I think another way to frame that is to ask, what is the difference between a myth and a model? Less than we might like to imagine, but there are differences that have to do with reproducibility and predictability. When an idea does nothing but unify, like MWI say, it is much more like myth than model. For example, if we say "Zeus is an angry god", then we can attribute everything violent and angry-seeming to "the will of Zeus". That is a vastly unifying concept-- we have unified in one fell swoop a vast array of "angry" phenomena-- "Zeus did it". But even so far-reaching a unification can be scientifically sterile when it does not predict and cannot be falsified. So a model is a testable myth, even though it is as unprovable as all myths.

 

[reilly]

I don't grant this much significance yet, reilly. I can't say whether these observations made in brain science are incompatible with free will or not because I don't know what free will is. I can only think of the vaguest of definitions.

I can grant that dislike of cooked turnips may not be a free choice. No taste is, whether it is a taste for Beethoven or a taste for torturing young boys. But what about the choice to act or refrain from acting on that taste? Christians, Muslims, etc. would say therein is the free choice.

But what is a free choice? I can't isolate it to say for certain whether anything is a "free choice" or not.

I find it interesting that such a fundamental questions of physics could be at all related to a fundamental question of morality and/or religion.

I'll dig up some references; there's a fairly large literature on the subject. Consciousness is being studied similarly. Definitions evolve as knowledge grows. In market research -- practical economics -- and neurophysiology, the point is to study behavior, and attempt to develop connections to brain states.That is, it's all about empirical evidence, something that has been applied to mental stuff for less than a century. Just as religion, at least in the West, had to change its world view during the Renaissance, science will drive society, in general, to new ways of thinking. My sense is that the idea of free will will eventually be thought of as a very simplified approach to aspects of human behavior. The need for that idea will diminish.

Note the changing attitudes toward mental illness and addiction, both of which I'm familiar with. We don't burn witches anymore; we don't view mental illness as a devilish intrusion. There is no such thing as free will, by any definition, for someone who is severely clinically depressed, or manic, or hearing voices or seeing things that are not there ...

So, not to worry, the lack of a good definition of free will is one of the reasons the concept is fading away -- at least in the brain science community.
Regards,
Reilly

 

[pellman]

So, not to worry, the lack of a good definition of free will is one of the reasons the concept is fading away -- at least in the brain science community.

If they are merely saying, "'free will' is not a proper subject for study within our science," and that within the bounds of their field it is an empty concept, I could grant them that. But if they go further and say it is an illusion or whatnot, I say they don't know what they 're talking about.

I highly recommend this little essay btw http://www.pseudobook.com/cslewis/wp-content/uploads/2006/09/meditation.pdf [Broken]

 

[keithbyron]

I am not sure that what i am about to post has much relevance but here goes.

I do not believe in free will or determinism. the way i see it, every single entity exists essentially in its "own" universe inside our universe. everything that you do has a reason, but that reason is only clear to you. from an outside view point that reason maybe seen as random or attributed to "free will" which is the same thing. the other thought that has been floating around my head is that what we term "free will" may be nothing more then the way the small electro magnetic field created by the brain interacts with the atomic and sub-atomic particles that make up our neurons at any given point in space-time. essentially there is a reason and no reason for everything that happens, and both are true at the same time.

 

[pellman]

.. and the energy levels of the harmonic oscillator are $$\hbar \omega(n+\frac{1}{2})$$.

Look! quantum physics!




Mods, please don't move my thread.

 

[peter0302]

The laws of nature would have to be precise for at least "12 billion" digits behind the
decimal point. Just to give some arbitrary high number. The way around the free will
dilemma is the fact that nature can never by infinitely accurate.

Why can't it? If there is some elemen of randomness in nature, be it at the 12 billionth digit or at the 34th digit (i.e. h) then we are back to randomness, and away from determinism. Determinisim and random are opposites.

 

[Ken G]

Why can't it? If there is some elemen of randomness in nature, be it at the 12 billionth digit or at the 34th digit (i.e. h) then we are back to randomness, and away from determinism. Determinisim and random are opposites.

It sounds like you are arguing it can be infinitely accurate, on the grounds that randomness seems unpalatable. I would point out that these two do not exhaust the possibilities, so failure to be infinitely precise does not imply fundamental randomness, and unpalatability of randomness does not require palatability of infinite precision. It all just means that all our concepts eventually break down, and I think we should not be surprised by that.

 

[Shackleford]

I feel I must briefly interject. Your implication in your creationist analogy is inaccurate. Evolution is inane and blatantly absurd. I'm a Christian, but it would take much more faith for me to believe in evolution than it would for me to believe that God created the universe and set in place all the physical laws, mathematics, and so forth. In fact, determining how the universe was created is completely outside the realm of science. Any such scientific claim for or against metaphysical assertions is inherently invalidated. Science is the study of how the universe works and the laws that govern them. Period.

 

[peter0302]

No, no, I'm not necessarily saying that randomness is problematic fundamentally. I just believe that conceptually random or deterministic are mutually exclusive possibilities. If one chooses deterministic, then nature is accurate to infinite precision. Anything short of infinite precision introduces randomness into the results, and we are back to traditional QM, just at a deeper level than 10^-34.

 

[peter0302]

Let me also add that randomness is not the same as imprecise. For example, if you try to calculate 1/3 on a 8-digit decimal computer, you will obviously get .33333333 every single time you run the program. However, if you try to calculate 2/3, you will get .66666667 each time. Extend that out a billion decimal places, and the results will still be the same _every time_. If there truly were randomness involved at the smallest levels, sometimes when you caluclate 2/3 you might get .666...667, and sometimes you might get .666...666, and sometimes even .666...665, etc. But you don't - you always get the same result every time, even though it's imprecise.

That's not randomness. That's still deterministic. It's just deterministic but imprecise. If nature is deterministic, then the randomness we see is due to our inability to observe more precise measurements. If nature is fundamentally random, then we will never be able to observre more precisely than roughly 10^-34.

 

[Ken G]

Science is the study of how the universe works and the laws that govern them. Period.

I believe that's pretty much what I said, I'm not sure where you imagine a contradiction. Personal beliefs are irrelevant to science, as science makes certain assumptions about the path to objectivity, involving experiment and demonstrability. Your beliefs about how the universe was created are not necessarily wrong, but they are scientifically sterile. And by the way, neither evolution, nor the Big Bang for that matter, are theories about the creation of the universe.

 

[Ken G]

I just believe that conceptually random or deterministic are mutually exclusive possibilities. If one chooses deterministic, then nature is accurate to infinite precision. Anything short of infinite precision introduces randomness into the results, and we are back to traditional QM, just at a deeper level than 10^-34.

I'm not sure if anyone doesn't agree with that-- I certainly do. I'm just saying we should avoid the implication that those choices exhaust the possibilities.

 

[reilly]

Don't forget that physics is an empirical science. Don't forget that any measurement has an associated measurement error --control engineers and statisticians investigate rather sophisticated models for non-normal error distributions, for temporal or spatial correlations, biases, ... This type of approach allows best estimates of the true measurement value (maximum likelyhood estimates, for example)

That's why I say both randomness and determinism are simply convenient myths. There is no way we can empirically determine whether randomness or determinism is appropriate for any system. Social scientists and statisticians are way ahead of most physicists in regard to randomness, determinism and causation.
Regards,
Reilly

 

[Ken G]

If nature is deterministic, then the randomness we see is due to our inability to observe more precise measurements. If nature is fundamentally random, then we will never be able to observre more precisely than roughly 10^-34.

But will those ever be distinguishable scientifically, even if it had to be one or the other?

 

[neu]

Personal beliefs are irrelevant to science, as science makes certain assumptions about the path to objectivity, involving experiment and demonstrability.

Therein lies another interesting discussion. I don't want to change the subject so I'll just refer you to an essay by Laura Snyder "is Evidence Historical?" in "Philosophy of Science: The Central Issues" M. Curd, J. Cover.

She proposes that there may be personal,as well as impersonal, reasons for belief in a "scientific" theory.

 

[foolosophy]

Qauntum mechanics is a stochastic analysis of the atomic world.

So by definition this analysis will overlay stochastic conclusions and predictions.

The usefullness of QM is not evidence FOR it being a perfect discription of the atomic world.

As Einstein said all along - the future will eventually produce a far more deterministic theory or model that will replace QM entirely.

Although QM is by far the greatest intellectual achievement of the human intellect, it will in the future be exposed as a completely fraudulant theory in so far as describing HOW atomic entities REALLY behave in nature.

amen

 

[peter0302]

But will those ever be distinguishable scientifically, even if it had to be one or the other?

Nope, determinisim v. randomness could never be proven empiraclly.

 

[Ken G]

She proposes that there may be personal,as well as impersonal, reasons for belief in a "scientific" theory.

Without seeing a relevant snippet from the article, I would tend to expect that she is mistaking what is a theory for what is a picture one can use to imagine a theory. This is a common problem for people who are not scientists (and even for a lot who are, it's a natural confusion).

 

[Ken G]

The usefullness of QM is not evidence FOR it being a perfect discription of the atomic world.

That is completely true.

As Einstein said all along - the future will eventually produce a far more deterministic theory or model that will replace QM entirely.

But he was guessing, as are you.

Although QM is by far the greatest intellectual achievement of the human intellect, it will in the future be exposed as a completely fraudulant theory in so far as describing HOW atomic entities REALLY behave in nature.

That would be impossible to do. It will always be an excellent theory-- theories never go from "excellent" to "fraudulent", that is another common misunderstanding about what science is. The only element of "fraud" that could ever appear is if people make the error of overselling what theories are (a mistake we do in fact see being made, it's true, but that's not the fault of quantum mechanics).

 

[Ken G]

Nope, determinisim v. randomness could never be proven empiraclly.

Right, which I say argues against the conclusion that they are mutually exclusive. This fact describes an overlap in the two, insofar as we are talking about scientific models. If we are instead talking about "reality", we would be wasting our breath, as neither determinism nor randomness, nor a combination or overlap, are likely to describe reality completely. Our minds are limited by our models as much as our models are limited by our minds.

 

[ThomasT]

We are discussing the Demystifier's paper "Quantum mechanics: myths and facts". http://xxx.lanl.gov/abs/quant-ph/0609163

Previously:
Myth 1 https://www.physicsforums.com/showthread.php?t=229497
Myth 2 https://www.physicsforums.com/showthread.php?t=230693

QM implies that nature is fundamentally random

The topic is the claim that the common statement that nature is fundamentally random--as opposed to merely unpredictable--is a myth. By myths we mean widely repeated statements which, true or false, are not something we can validly assert given our current understanding.

By this definition of myth, then the statement can be called a myth.

I would just call it a silly statement.

One problem is with the word, fundamentally. If we take the words random and deterministic to mean unpredictable and predictable, respectively, then nature presents itself to us as both random and deterministic.
The quantum theory can predict ensemble data quite accurately. However, the outcomes of individual trials are pretty much unpredictable. Does this imply that nature is fundamentally random? Of course not. There's just no way to predict the outcomes of certain experiments. (The hopelessly unpredictable and fundamentally random data of one century might become the regularly predictable and produced data of the next.)

The essence of the Copenhagen interpretation of the quantum theory -- which is the philosophical foundation of the most widely used "shut up and calculate" and/or "probabilistic" interpretations of the theory -- is that the existence of a fundamental quantum of action precludes us knowing what nature fundamentally is.
Thus, to paraphrase Bohr, the task of physics can't be to know what nature is. Rather, the task involves what can be said, unambiguously, about the various physical phenomena that our sensory faculties present us with.

The quantum theory was not developed as a description of fundamental reality. It doesn't pretend to be a window to a world that we'll never directly sense. It shouldn't be taken as a model of some quantum world beneath the level of our sensory apprehension. The point of departure in the development of the theory is, eg., spectrographic data itself, not its cause.

According to QM, we can't -- ever -- know that nature is fundamentally this or fundamentally that. So, to say that QM implies that nature is fundamentally this or that goes against the nature of the theory, so to speak.

Now, one might wonder how, if QM isn't about fundamental reality, the theory can (based as it is on the existence of a fundamental quantum of action) forbid our ever knowing the foundation(s) of nature. That is, what's all this fundamental quantum of action stuff? What does fundamental mean in this context?

 

[StatusX]

The topic is the claim that the common statement that nature is fundamentally random--as opposed to merely unpredictable--is a myth.

I don't see a meaningful distinction between random and unpredictable, at least if by unpredictable you mean "cannot in principle be predicted." If instead you just mean "can't be predicted by current theories," I'll agree there is a distinction, but personally disagree that any future theory will take away the uncertainty of QM.

And somehow this multitude of things happening for no reason conspires to create the visible macro order? I can't accept that.

This is very similar to another creationist fallacy, the notion that evolution is just the theory that we got to be the way we are by pure chance. In both cases (evolution driven by essentially random genetic mutations and QM), small scale randomness is shaped by large scale principles to create an outcome that is orderly, if not entirely predictable. For example, even though each individual electron hitting a screen in a double slit experiment is subject to a certain degree of randomness regarding where it ends up, the underlying probability distribution means that, after many trials, an orderly pattern will emerge on the screen.

We say of a supposed random event, "It could turn out A or B". Afterwards, we say that although B happened, it could have been A. What do we mean by "could have been"? B happened, period.

It means that if an identical experiment were performed, the result could be B.

 

[peter0302]

It means that if an identical experiment were performed, the result could be B.

That's what randomness in principle means. Determinism, on the other hand, means that in principle if all starting conditions were identical the result would always be A. I don't see why that distinction is meaningless. Can we replicate all starting conditions? No, obviously not, not for the whole universe. So, for now, it would appear we cannot test the distinction. It is, therefore, not a scientific statement. But I disagree with those that say it's meaningless.

 

[Ken G]

Thus, to paraphrase Bohr, the task of physics can't be to know what nature is. Rather, the task involves what can be said, unambiguously, about the various physical phenomena that our sensory faculties present us with.

Yes, I agree with you that Bohr had it right on. You can take any physics theory and any general attribute of that theory and plug them into the sentence "The theory _____ tells us that nature is fundamentally ________", and all you have there is an automatic myth-generator (or "silly statement generator"). The simple truth is that it is not any theory's job to tell us what nature fundamentally is, the whole point of a theory is to replace that impossible task with something possible. The only meaningful use of the word "fundamental" in physics is to mean "does not stem from any other theory"-- in other words, it describes a relation between theories, not a relation between theory and nature.

 

[Ken G]

So, for now, it would appear we cannot test the distinction. It is, therefore, not a scientific statement. But I disagree with those that say it's meaningless.

I agree there is a distinction between "random" and "inherently unpredictable", and that the distinction disappears when you project it onto what science does. The distinction is that the former is a statement about what is present (i.e., randomness in a distribution), and the latter is a statement about what is absent (i.e., complete predictability). For there to be no distinction, it requires both that they overlap, and that the union of either with the inverse of the other must exhaust the possibilities. I claim the union of "random within a predictable distribution" with "completely predictable" does indeed exhaust the possibilities of science (though not the possibilities of nature) for the simple reason that the latter is merely an example of the former in the limit of a very narrow distribution. The real question is, how can science make a model that does not conform to random choices within some distribution, possibly an unresolvably narrow one? I don't think it can-- but our brains can (witness my religion analogy).

 

[peter0302]

Agreed.

Another way one might look at it, a pseudo-proof if you will:

Let us assume in a perfect universe that observing some "thing" 'A' requires, at a minimum, it to interact with some other "thing" 'B'. Let us also assume that predicting a future interaction between 'A' and 'B' requires an earlier observation of both 'A' (interacting with "thing" 'C') and 'B' (interacting with "thing" 'D').

Therefore, in order to make any prediction about 'A', we need no fewer than three additional "things" 'B', 'C', and 'D'. One quickly sees that knowledge about any "thing" always requires additional "things" to come into the equation, about which we will always initially lack knowledge, and about which we cannot obtain more knowledge without introducing more "things". So we can see through this that "Nature" is inherently unpredictable in principle because we simply cannot know all there is to know about every "thing": every time we learn about one "thing", more "things" become unknown simply through the act of learning about the first "thing". Like smacking worms at a carnival game.

But this only proves a fundamental limitation on our ability to obtain knowledge, and not, necessarily, a fundamental randomness. To me, the latter is more of a leap of faith than the former, as the former flows logically from what I think are self-evident assumptions. Thus, I'd say that QM proves that nature is inherently unpredictable and that, indeed, Demystifier's third "myth" is indeed a myth.